<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>四则运算</title>
	</head>
	<body>
		<script>
			var num1=parseInt(prompt("请您输入第一个整数："));
			var ysf=prompt("请您输入运算符：（1.+ 2.- 3.* 4./)");
			var num2=parseInt(prompt("请您输入第二个整数："));
			
		if(ysf=="1"){
			document.write(num1+num2);
		}
		if(ysf=="2"){
			document.write(num1-num2);
		}
		if(ysf=="3"){
			document.write(num1*num2);
		}
		if(ysf=="4"){
			document.write(num1/num2);
		}
		</script>
		
	</body>
</html>
